It is known that high melting point tetrafluoroethylene polymers such as polytetrafluoroethylene homopolymer (PTFE) dissolve in relatively high boiling point solvents, see for instance P. Smith and K. Gardner, Macromol., Vol. 18, 1222-1228 (1985). Lower boiling point compounds, such as the lower perfluorinated alkanes usually do not dissolve polymers such as PTFE under autogenous pressure. It is believed that to dissolve PTFE under autogenous pressure a compound with a critical temperature above about 340.degree. C. is needed (see commonly assigned U.S. patent application Ser. No. 07/936,449, filed Aug. 28, 1992).